Method and apparatus for machining belts



Nov. 22, 1966 G. c. GILBERT ET AL 3,286,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13. 1962 14 Sheets-Sheet 1 INVENTORS {ff/ 67 f (Q/ierf BY Jar)? 1Q Z/f/a/(OZ M v IXTTORNEYS 1966 G. c. GILBERT ET AL 3,286,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet E i i K [K1 IN VEN TORS 62/18)"! Z. f/Kerf W If q/ 11 T2 )RNE YS NOV. 22, 1966 13. GlLBERT ETAL 3,286,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13. 1962 14 Sheets-Sheet 5 INVENTORS 6i/Zer5 C i/ier'f BY Ja /& za 592:

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METHOD AND APPARATUS FOR MACHINING BELTS Original 'Filed April 13, 1962 14 Sheets-Sheet'4 NOV. 22, 1966 c, GILBERT ET AL 3,286,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet 5 INVENTORS Gi/Aerz" K. z'fierf BY @6122 inf/awn M w, M

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METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet 6 Nov. 22, 1966 e. c. GILBERT ET AL 3,236,563

METHOD AND APPARATUS FOR MACHINING BELTS INVENTORS 6' 1/1 32 2 5 fi/irf BY dC// Z K/b JJZz l4 Sheets-Sheet 7 A TTO 1 EYS Nov. 22, 1966 G. c. GILBERT ET AL 3,235,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 15. 1962 14 Sheets-Sheet 8 I. w ww\ suq \\\N\ O I k. Q l 1 I N\\ O 1 ml l w llllllllllllll l llll i l m m m m 5 1675 (.{zKJerf BY $267? )2. Z/[f/(QE M JZWW, W, W 4 N W 1966 G. c. GILBERT ET AL 3,286,563

METHOD AND APPARATUS FOR MACHINING BELTS l4 Sheets-Sheet 9 Original Filed April 13, 1962 INVENTORS III/III;

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METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet 10 ATTORNEYS Nov. 22, 1966 G. c. GILBERT ET AL 3,285,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet ll Nov. 22, 1966 e. c. GILBERT ET L 3,236,563

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet 12 INVENTORS fz/jerafiz/lfrf law/M ,rr ORNISYS Nov. 22, 1966 G. c. GILBERT ETAL 3, 3

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets-Sheet 15 INVEN TORS I z' jerff z/ierf BY Jaw? JZ. Mf/daz M W1 W H'TORNEYS Nov. 22, 1966 e. c. GILBERT ET AL 3, 3

METHOD AND APPARATUS FOR MACHINING BELTS Original Filed April 13, 1962 14 Sheets$heet 14 INVENTOR5 5/ 6.97"! [Kr/A97 5 BY Jazz)? )6. ll zl /car United States Patent 3,286,563 METHOD AND APPARATUS FOR MACHINING BELTS Gilbert C. Gilbert, Beloit, Wis., and Jack A. Willcox,

Rockford, Ill., assignors to Beloit Corporation, Beloit,

Wis., a corporation of Wisconsin Original application Apr. 13, 1962, Ser. No. 187,376, now

Patent No. 3,240,091, dated Mar. 15, 1966. Divided and this application June 28, 1965, Ser. No. 478,005

33 Claims. (Cl. 83-5) This application is a division of our copending application, U.S. Serial No. 187,376, filed April 13, 1962, now Patent No. 3,240,091.

This invention relates generally to a method and means for machining a belt, and more specifically to an improved apparatus and method for grooving and punching a massive rubber belt.

Although the principles of the present invention may be included in various devices and methods, a particularly useful application is made in connection with the machining of massive rubber belts. boxes of paper making machinery employ such a belt, and by way of illustration, such a belt may have a width of twenty-five feet, a length of thirty-five feet, and a mass so great that the same can be handled best by a crane during installation, removal, and handling thereof. A belt of this type is typically employed between the Fourdrinier wire and the suction box of a paper making machine, and to that end is provided with perforations therethrough which terminate in elongated grooves directed toward the Fourdrinier wire. To adapt such a massive rubber belt to such a usage, it therefore is necessary to provide such grooves and perforations. In a belt of this size, many thousands of grooves and perforations are required.

An unmachined belt of this type, even though it may be internally reinforced, has a certain amount of internal tension which is released or which yields in response to a large amount of machining such as that contemplated. Therefore, the actual belt size and the relative spacing between grooves and perforations have tended to change during the course of machining of the belt. Since a relatively high degree of precision is required in the Placement of the grooves and perforations so as to register properly with the suction box structure, it has been con sidered heretofore impractical to machine such belt other than by hand. It is evident that such a hand-finished belt becomes extremely costly.

Accordingly, it is an object of this invention to provide an apparatus for machining a massive belt.

A further object of the present invention is to provide a method and apparatus for machining a belt, the size of which belt is susceptible to growth during the progress of the machining.

A still further object of the present invention is to provide a method and means for stabilizing internal belt tensions so that subsequent belt growth during subsequent machining may be reasonably accurately predicted or compensated for.

Yet another object of the present invention is to minimize or eliminate hand operations for grooving and/or perforating a belt by adequately compensating for dimen sional changes encountered.

A still further object of the instant invention is to provide a method and apparatus for providing a precision uniform predetermined pattern in a suction belt which will produce a uniform and rapid drainage of water into and through the belt.

Attempts have previously been made to machine rubber belts by employing milling or grinding techniques. However, such techniques produce rubber dust, thereby creating fire and explosion hazards which have necessitated performance of the machining under water.

In particular, suction- 3,286,563 Patented Nov. 22, 1966 Accordingly, a further object of the present invention is to provide a method and apparatus for machining a massive rubber belt without use of milling or grinding of rubber, and without performing any machining under water, and yet avoiding fire and explosion hazards.

A further object of this invention is to machine large non-rigid belts at relatively high speed, the machining being of a precision nature, and the belt being one which grows as the result of machining.

A further object of this invention is to provide a cutting method and means which continually compensate for belt growth.

Belts of the type described typically employ a wire reinforcement embedded therein. Heretofore, the provision of numerous holes therethrough has tended to expose short lengths of reinforcing material such as wire which hangs loosely in the adjacent hole.

Accordingly, a further object of this invention is to provide a punch shape which will neither crimp n-or expose lengths of reinforcing wire.

Experience has also taught that simultaneous grooving and punching is disadvantageous from a quality standpoint. However, the separation of these operations has been previously accomplished only at a great sacrifice of time and cost.

Accordingly, it is a further object of this invention to minimize such time and cost.

It has also been learned that belt life may be lengthened when the holes in the belt are arranged in a staggered fashion. 7

Accordingly, yet another object of the instant invention is to provide apparatus which will produce belt perforations or holes arranged in a staggered fashion, the pattern of staggering being relatively unrestricted or flexible, and each hole being accurately located.

With an extensive amount of machining to be accomplished on each belt, a problem also arises in connection with removal of the belt material which has been freed by machining. A further problem arises in that the progress of machining should be so disposed as to be readily available for visual inspection even though the belt is of a massive size. Further, adequate support must be pro vided so that neither the suppont nor the belt sags during machining, because distortion due to sagging would destroy the precision nature of the machining required.

Accordingly, it is an object of the present invention to dispose the portion of the belt being machined in a vertical plane to facilitate waste removal, visual inspection, and antisag stiffening.

Yet another object of the present invention is to provide a grooving machine for a rubber belt which is capable of producing grooves which are slightly overlapped at their ends, either near the edges of the belt, or anywhere in the central portion of the belt.

A still further object of the present invention is to provide a machine of the type described capable of handling massive workpieces, which machine is simple and which entails a minimum of original and operating cost.

A still further object of the present invention is to provide a machine of the type described embodying an indexing mechanism which compensates for belt stretching and growth and for any sagging which may occur in a vertical span of the belt so as to minimize spacing error in grooving the same.

Yet another object of the present invention is to provide a method and means for grooving and/or perforating a massive rubber belt wherein the accuracy of groove and perforation location is precisely established by the machine.

Yet another object of the present invention is to compensate for any clutch slippage or slippage between the belt and a roll by directly sensing actual belt movement,

and by using an indication thereof to regulate the magnitude of belt indexing or movement.

Yet another object of the present invention is to provide a method and means for driving and retracting a cold grooving cutter so as to effect a smooth cut in a rubber belt.

A still further object of the present invention is the provision of means whereby -a relatively delicate grooving knife may be rapidly handled without the same being susceptible to breakage.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIG. 1 is a side elevational view of a belt machining apparatus provided in accordance with the principles of the present invention, certain parts being omitted or broken away to clarify the illustation;

FIG. 2 is a fragmentary elevational view of a belt illustrating a portion of a typical grooving and punching pattern provided in the belt;

FIG. 3 is a plan view of a drive mechanism for the beltsupporting means illustrated in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a clutch and brake assembly illustrated in FIG. 3;

FIG. 5 is a front view of the drive mechanism of FIG. 3 showing its driving connections with the belt-supporting means of FIG. 1;

FIG. 6 is a side view of the drive mechanism shown in FIG. 3;

FIG. 7 is a fragmentary front elevation of the machine shown in FIG. 1;

FIG. 8 is an enlarged detailed view of a belt movement sensing mechanism illustrated in FIG. 1;

FIG. 9 is a bottom view of a portion of FIG. 8;

FIG. 10 is an enlarged side elevational View of a grooving head assembly illustrated in FIG. 1;

FIG. 10a is an enlarged fragmentary cross-sectional view taken along line XaXa;

FIG. 11 is a further enlarged and sectioned view of a portion of the cutter head assembly and belt illustrated in FIG. 10;

FIG. 11a is a fragmentary enlarged view taken along line XIa-XIa of FIG. 11;

FIG. 12 is an enlarged top view of the grooving head assembly illustrated in FIG. 10, the same being partially broken away for clarity of illustration;

FIG. 13 is a side elevational view, taken from the opposite side, of a further machining head employed for perforating the belt by punching;

FIG. 14 is an elevational view of the punching head assembly of FIG. 13 as viewed from the belt;

FIG. 15 is an enlarged diagram illustrating the configuration of the rubber to be removed from the belt during punching;

- FIG. 16 is a side elevational view of a still further machining head employed to punch and to groove the edges of the belt;

FIG. 17 is a fragmentary view of the belt illustrating the grooving and punching pat-tern near the edge of the belt, as produced by the machining head of FIG. 16;

FIG. 18 is a plan view of the machining head of FIG. 16;

FIG. 19 is an elevational view of the machining head of FIG. 16 as viewed from the belt;

FIG. 20 is a fragmentary view of a belt, largely diagrammatic in nature, and shown in scale that is reduced from that employed in FIGS. 2 and 17;

FIG. 21 is a fragmentary elevational view of an adjustable locating template; and

FIG. 22 is a side elevational view of a head locating mechanism, a portion of the figure being in cross-section and taken along line XXII-XXII of FIG. 21.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a belt machining device such as illustrated in FIG. 1, generally indicated by the numeral 20. The machining device 20 includes a belt support structure generally indicated at 21, a belt driving and indexing mechanism generally indicated at 22 and shown in FIG. 3, a head support structure generally indicated at 23 which carries a series of machining heads, and of which series of machining heads a grooving head assembly 24 is illustrated in FIG. 1. The machining heads include a punching head assembly 25, and a decal grooving and punching head assembly 26, both omitted from FIG. 1 for clarity, but shown separately in FIGS. 13 and 16 respectively. Although the various components coact on a single belt to produce a unified result, for convenience, the various components of the machine are separately discussed.

.Brlt support structure 21 The belt support structure 21 includes a plurality of elongated parallel beams 27 which jointly support a slide 28 which extends transversely thereto. The slide 28 is movable in the direction of the beams 27 by means of a number of air cylinders 29 which are adjustably secured to the beam 27 at a selected position. A belt B extends around a group of three inside rolls 30, 31 and 32 and against an outside roll 33. The roll 30 is a stretch roll which is rotatably supported on the slide 28, the roll 30 imparting a constant tension to the belt B by action of the air cylinders 29. The roll 33 is supported by bearing housings 34, each of which is secured to a screw slide 35 carried by a pair of brackets 36 secured to the lower portion of the slide 28. The slide 28, the rolls 30 and 33, the bearing housings 34, the screw spindles 35, and the brackets 36 move as a unit in response to the air cylinders 29 while supported on the beams 27 to impart a constant tension to the belt B. Positioning of the screw spindles 35 relatively repositions the guide roll 33 for guiding the belt B in a cross-machine direction.

The inside rolls 31 and 32 are rotatably supported at their ends by bearings secured to a cantilevered backup beam 37 shown in cross-section, the broken away supporting portion being secured to and supported by the nearer beam 27, such portion being partially illustrated at 38 in FIG. 5. The roll 31 comprises a drive roll, it being driven as is explained later herein. The lower roll 32 is an idler roll which disposes a portion of the belt B in a vertical plane parallel to the front face of the backup beam 37. It is to be understood that the air cylinders 29 can be selectively relocated on the beams 27 to adapt the machine 20 to different lengths of b'elt B.

Each of the rolls 31 and 32 has an extended journal directed toward the viewer, each of which is rotatably supported by a pair of pillow blocks 39, seen also in FIG. 5. As best seen in FIG. 7, the opposite ends of the rolls 31 and 32 are each provided with a journal, each of which is rotatably supported by a pillow block 40. The pillow blocks 39 and 40 are secured to the cantilevered backup beam 37. As best seen in FIG. 7, during normal operation, the free end of the cantilevered backup beam 37 is supported by an arm 41 which is pivotally mounted as at 42, the arm 41 normally being held in tight supporting engagement with the backup beam 37 by a cylinder 43 acting through a cable 44. Upon release of cable tension by extension of the cylinder 43, the cable 44 may be loosened so that the arm 41 may pivot to a horizontal position to enable installation and removal of the belt.

Due to inherent resiliency, the free end of the backup beam 37 illustrated in FIG. 7 may be deflected into and out of proper alignment. To insure that the arm 41 steadies the backup beam in a position which is proper, the same is made vertically and horizontally (perpendicularly to the drawing) adjustable. In FIG. 7, vertical adjustability is indicated as being provided by a shim or wedge 42a of suitable .thickness, while horizontal adjustability is provided through a number of attachment screws 42b which extend through slots in the pivot base. It will be understood that the vertical and horizontal adjustability of the arm 41 may be effected in numerous manners.

Referring again to 'FIG. 1, it will be noted that the journals of the roll 30 are pivotally supported by a split member 45. With the split member 45 loosened, an overhead crane can lift the belt B by hoisting the stretch roll 30, then moving the same in a cross-machine direction to slip the belt B off the free ends of the rolls 31 and 32. It is to be understood that a structure such as shown in FIG. 7 could also be provided for the stretch roll 30, it being suitably supported at the opposite end, to thereby enable a fork lift truck to handle the belt B. After the roll 30 and belt B have been carried away by the crane, the roll may be slipped out and associated with the next belt to be machined. The process is then reversed for installing the same on the belt support structure 21.

It is evident that the belt B is thus rotatably supported under constant tension for continual or intermittent movement in either direction. The mechanism for obtaining such movement is discussed beginning at the following paragraph.

Belt driving and indexing mechanism 22 The belt driving and indexing mechanism 22 is illustrated in FIGS. 3-6. Referring to FIG. 3, the mechanism 22 includes an electric motor 46 which is drivably connected to a speed reducer 47, the output of which is connected to a gearbox 48 to rotate a shaft 49 by means of a coupling 50. The motor 46, speed reducer 47, and gearbox 48 jointly comprise an electrically driven variable speed drive of known construction, the output of which is a constant speed determined selectively by the position of a speed selector 51. The shaft 49 is rotatably supported by bearings 52, 53. Encircling the shaft 49 is an electromagnetic clutch 54 and an electromagnetic brake 55, between which is a sprocket 56.

Referring to FIG. 4, the electromagnetic clutch 54 has an inner portion 54a which is keyed as at 57 to the shaft 49, and an outer portion 54b. The electromagnetic brake 55 has an inner portion 55a which is secured in fixed position to a bearing support 58, and an outer portion 55b. The sprocket 56 is clamped between a pair of clamping blocks 59, 59 for corotation therewith, the clamping blocks 59, 59 being respectively secured to the outer casing 54b of the clutch 54 and the outer casing 55b of the brake 55. Suitable bearings are provided for the clamping blocks 59 so that the radial load on the sprocket 56 is not carried by the clutch and brake. It is thus evident that the outer casings of the clutch 54 and brake 55 are corotatable with the sprocket 56 as a unit. The clutch 54 includes a slip ring 54c which is energized from an electric brush 60 (FIG. 3). When the clutch 54 is energized, the sprocket 56 is corotatable with the shaft 49. When the brake 55 is energized, the sprocket 56 is locked to the bearing bracket 58 whereby rotation of the sprocket is prevented. The shaft 49 passes through the brake 55 and is free to rotate therein. When neither the brake nor the clutch are energized, the sprocket 56 is neither driven nor locked. When the clutch 54 is energized and the brake 55 deenergized, the sprocket 56 is driven, and when the clutch 54 is deenergized and the brake 55 energized, the sprocket 56 is locked. It is to be understood that the clutch and brake are alternatively energized. The structure for controlling the same is described later herein.

Referring again to FIG. 3, the sprocket 56 through a main drive chain 61 drives a sprocket 62 which is corotatably secured to a rotatable shaft 63. The shaft 63 carries a pair of freewheeling sprockets 64, 65, to each of which sprockets there is secured a portion of a clutch,

here illustrated at 66 and 67 as being a portion of a dog clutch or jam coupling. The clutch portions 66 and 67 are corotatable with the associated sprockets and also thus turn freely wit-h respect to the shaft 63. The other portion of the clutches 66, 67 is shown at 68, the same being keyed to the shaft 63 to be corotatable therewith but slidable axially thereon in response to movement of a handle 69. Movement of the handle 69 to the left engages the portion 68 with the portion 66 to drive the sprocket 64 continually for effecting continual belt rotation. The portion 68 is engageable with the clutch portion 67 to drive the sprocket 65 to obtain inter-mittent or indexed belt movement. To this end, the sprocket 65 drives a chain 70 which in turn drives a sprocket 71 corotatably carried on a shaft 72, .to the end of which there is secured a plate 73 on which there is carried an adjustable eccentric generally indicated at 74, movement of which reciprocates an indexing arm 75. The adjustable eccentric 74 includes an adjustment bolt 76, the position of which determines the magnitiude of eccentricity and hence the magnitude of reciprocatory movement of the indexing arm 75. The indexing arm 75 and a chain 77 on the sprocket 64 are each connected to drivably rotate the drive roll 31 as best seen in FIGS. 5 and 6.

The chain 77, which is continually drivable by the sprocket 64, is drivably connected to a sprocket 78 which is corotatably secured to the shaft 31a or journal of the roll 31. Thus, when the handle 69 is positioned to engage the clutch 66, 68, the electromagnetic clutch 54 being energized, the drive roll 31, and hence the belt B, is continually driven at a constant speed. If the electromagnetic clutch be deenergized, or if the handle 69 be moved to a central position as illustrated, the belt will coast, but if the brake 55 be energized with the handle 69 left in a clutch-engaging position, the belt movement will be immediately braked.

The indexing arm 75 is reciprocated at its lower end 75a by the eccentric mechanism 74, and at its upper end, the indexing arm 75 is carried by the drive roll shaft 31a in a free manner. As best seen in FIG. 5, the drive roll shaft 31a also supports a pair of ratchet clutches 79, 79, each of these comprising a one-way clutch of known internal construction, and having an adaptor plate 79a 79a, adapted to be alternatively driven by the indexing arm 75. To this end, a dowel pin 80is provided to form a selectable connection between the indexing arm 75 and one of the adaptor plates 79a. The clutches 79, 79 are each one-way clutches, but each is adapted to drive the ournal shaft 31a in an opposite direction. It is therefore evident that each complete cycle of the eccentric mechanism 74 will produce movement of the drive roll 31 n a selected direction, until the movement of the indexing arm 75 is reversed, thereby causing the corresponding or selected ratchet clutch 79 to slip. In a preferred embodiment, the eccentric mechanism 74 is not employed to determine the magnitude of belt movement, but preferably other means described below responsive to actual belt movement are employed to control operation of the clutch 54 and brake 55, whereby the desired increment of belt movement may be greater than or lesser than one full stroke or cycle of the indexing arm 75.

The various fixed components of the mechanism 22 described are secured to a base plate 81 which is rigidly secured by appropriate bracketing to the beam 27 so as to be fixedly carried. There is also provided a power supply 82 of a conventional type for the clutch 54 and brake 55.

It :is contemplated that the grooving and punching described below will be carried out with the belt B in a stationary locked position, or succession of stationary locked positions. The purpose therefore of the continual drive mechanism including the clutch 66, 68, the sprocket 64, the chain 77, and the sprocket 78 is therefore here explained. We have found that the internal tensions of a fresh unmachined belt are subject to considerable variations and can be stabilized by an appropriate treatment. Accordingly, after the fresh belt has been installed as shown in FIG. 1, and the guide roll 33 has been properly adjusted, the clutch handle 69 is positioned to drive the belt support rolls through the chain 77, the electric clutch 54 being energized. As previously explained, this produces a continual rotation or running of the belt B about a plurality of axes defined by the various trolls. During this operation, a normal tension is applied to the belt through the air cylinders 29. It has been found that if the belt B is thus rotatably driven for a substantial period of time, the various internal tensions in the belt become stabilized so that the belt can thereafter be machined, namely be provided with grooves and holes at relatively closely dimensioned locations, for example with an error not exceeding approximately plus or minus /6 of an inch within a pattern segment, such tolerance being nonaccumulative. The belt B is thus rotated for a period of time sufiicient to stabilize the internal tensions.

A simple reliable indication of stabilization of such internal tensions has also been discovered. The fresh belt, with the guide roll 33 and backup beam 37 properly adjusted, will appear to track properly when so rotated. However, continued rotation releases various tensions, and the belt position drifts by an unpredictable amount. However, when the belt has been so rotated for a while, such drifting disappears, and thus we have learned that the cessation of drifting evidences that the internal belt tensions have been stabilized. This relationship has been found to be true in actual practice. A preferred method of sensing such drift is to provide a reference marking on the belt which extends along its length, such as near its center. This mark will be disposed substantially adjacent to a pointer 27a (FIG. 1) carried by a bracket 27b secured to one of the beams 27. The use of a central mark avoids possible confusion between lateral belt drift and lateral belt growth. Thus, when the belt achieves a stable effective length and position as a result of continual rotation in the manner described, the belt is ready for precision machining, namely accurately providing precisely located grooves and apertures. When this is to be done, the clutch handle 69 is moved to its opposite limit of travel to enable transmission of power through the chain 70 and the adjustable eccentric 74, through the indexing arm 75 and the one-way clutch 79 to the drive roll 31.

To control the indexing mechanism 22 so as to drive the belt B by a proper predetermined amount, there is provided a pivotally supported odometer generally indicated at 83 in FIG. 1 pivotally supported by a bracket 86 secured to the cantilevered backup beam 37. The odometer 83 is biased against the belt B and is responsive to the actual movement thereof. The odometer 8-3 is operative to electrically regulate the electromagnetic clutch 54 and the brake 55 in response to a predetermined actual movement of the belt B. It will be appreciated that various structures of odometer 83 will achieve this result, a representative structure being shown in FIGS. 8 and 9. The odometer 83 includes an arm 84 pivotally supported at 85 on the bracket 86 which is secured to a stationary part of the machine such as the backup beam 37. There is provided a disk or wheel 87 which is rotatably mounted on the arm 84 and which has a periphery 87a which is adapted to frictionally engage the belt B. For this purpose, the surface 87a has been illustrated in FIG. 9 as being a straight spline. Adjacent to the wheel 87, there is disposed a shaft 88 on which is carried a friction wheel 89 which is selectably positionable in fixed positions along the shaft 88 to obtain the proper ratio or measured movement. The shaft 88 drives a gear 90 which meshes with a gear 91 carried on a shaft 92 rotatably supported in a bracket 93 secured to the arm 84. The shaft 92 carries a cam 94 which, once per cycle, effects a reciprocatory cycle of a switch follower 95a of an electric switch 95, which is connected through an appropriate circuit to the clutch 54 and the brake 55 to deenergize the clutch and to simultaneously energize the brake in response to a predetermined magnitude of movement of the belt B. Near the ends of the shaft 88, there are provided spring loaded journal supports '96 which maintain the friction wheel 89 in contact with the surface of the disk 87. It is evident that one revolution of the cam 94 represents a certain predetermined belt movement, the magnitude of which is dependent upon the axial position of the adjustable friction wheel 89. In a specific example given later herein, the friction wheel 89 is so set as to produce one revolution of the cam 94 in response to one and one-half inches of belt movement, Such would be the movement if two grooves were made at a time, the centers of the grooves being spaced three-fourths inch apart. In a preferred embodiment, the electromagnetic clutch and brake 54, 55 are also provided with manual controls which may be momentarily operated to inch the mechanism 22 along, for example, to place the belt at a predetermined starting position from which increments of movement are measured. The pivotal support of the odometer 83 thus enables raising of the same to preclude unwanted interaction, and to preclude unwanted operation of the electric clutch and brake during continual rotation of the belt. It is also evident that the odometer may be left engaged with the belt as drawn in FIG. 1 during any such inching along of the belt, in which case the odometer would remember the predetermined position or reference point.

Before grooving or punching is done, after the belt has been run-in, the intermittent drive mechanism 22 for the belt is operated through one cycle of the belt, the adjustable friction wheel 89 being axially repositioned as may be required to produce the desired number of arrested movements in one belt cycle. It has been stated earlier that machining of the belt causes a further change in the belt length. Although such growth is minimized by the run-in described, it is sometimes convenient to reset the adjustable friction wheel 89 by a small compensating amount when a small amount of the belt remains to be machined, namely five or ten percent, so as to equally distribute the remaining machining operations in the remaining unmachined portion of the belt. It is evident that under certain circumstances this may also be done by the inching method referred to above.

For the smoothest operation of the machine as a whole, it is recommended that the eccentric mechanism 74 be adjusted to have a stroke substantially equivalent to the position of the adjustable friction wheel 89, even though a wide disparity between these settings does not adversely affect the accuracy of the machine.

It is thus evident that use of an odometer as described compensates entirely for any slippage between the belt and the drive rolls, for linear growth in the belt, and the like.

Where the grooving is carried out prior to the punching, the odometer constitutes an ideal means for accurately controlling the successive positioning of the belt. However, it is to be understood that in certain instances, such as in connection with perforating the belt, a visual monitoring of the amount of indexed movement, the use of a template, or the like, may also be advantageous. In any event, some slight resetting of the adjustable friction wheel 89 prior to perforating a grooved belt may be anticipated.

Head support structure 23 Referring again to FIG. 1, the head support structure 23 includes a pair of elongated tracks or rails 97, 98 supported on a track and template support 23a and extending transversely to the machine and parallel to the backup beam-37 and parallel to the axes of the rolls 31, 32. The tracks 97, 98are stationary and have an elongated configuration which preferably is somewhat greater than the width of the belt B. Thus, for example, if the belt B is twenty-five feet in width, a typical length for the tracks 97 and 98 would be fifty-five feet. A gear rack 99 extends substantially coextensively with the track 98, and is secured in fixed relation to the track 98. Each of the machining heads, such as the grooving head assembly 24 shown in FIG. 1, is provided with suitable means for supporting the head on the tracks 97 and 98 so as to be movable thereon, and, to effect such movement, a suitable mechanism having a driving engagement with the rack 99 is provided. Thus, by way of example, the head assembly 24 includes an electric motor 100 acting through a speed-reducing gear assembly 101 to drive a gear 102 which is in mesh with the gear rack 99.

To provide power to the motor 100, to provide compressed air to the head assembly 24, and to provide other appropriate control thereof, each head, such as the machining head 24, includes a cable 103 which comprises an assembly of all of the different hoses and wiring required. Since the head 24 is movable for a considerable distance on the tracks 97 and 98, the cable 103 of hoses and wiring is of considerable length and is supported at intervals along its length by one or more trolleys 104 supported by a fixed overhead monorail 105. The other ends of the hoses and cables (not shown) are connected to appropriate supplies or controls.

Disposed substantially coextensively along the tracks 97 and 98, there is a group of rods having movable trip dogs thereon, jointly indicated at 106, the rods being supported at intervals along their length by suitable bracket structure 107. The trip dogs coac-t with a group of limit switches 108 which are arranged to provide appropriate control of various elements in response to a predetermined movement of the machining head 24 on the tracks 97 and 98. It will be appreciated that the control that may be provided by the rod and dog assemblies 106 and the switches 108 may also be manually provided, and the details of such control are therefore not necessary to a full understanding of the instant invention.

As stated above, the device 20 includes a number of different machining heads of which the head 24 is representative. By way of example, one or more grooving heads 24, punching heads 25 (FIGURE 13), and edge punching and grooving heads 26 (FIGURE 16) may be provided. It is to be understood that each of these heads may include features corresponding to those thus described for the head 24 shown in FIGURE 1. Further, if the pattern admits of same, more than one head may act on a different portion of the belt B at the same time. We have found that one simple way of insuring that any head not in use will not inadvertently operate is to provide a suitable switching means to all power leading thereto. A simple example thereof requiring no structure for such purpose is simply a method step, namely the step of disconnecting the cable 103 at either end thereof.

Grooving head assembly 24 The grooving head assembly 24 is generally illustrated in FIGURE 1, but is shown in enlarged detail in FIG- URES -12. The grooving head assembly 24 includes a cutter support 109 disposed adjacent to the belt B, the cutter support 109 being rotatable incrementally about a vertical axis, its position being further adjustable vertically, and horizontally, both parallel to and perpendicularly to the direction in which the tracks 97, 98 extend.

To achieve proper cutter ositioning, the grooving head assembly 24 includes a base plate 110' slidably supported on the tracks 97, 98 as by bearings, and being movable therealong by operation of the motor 100 acting through the gear train 101 to drive the gear 102 as explained before. This structure achieves translation of the cutter support 109 in a direction parallel to the tracks 97, 98. This motion may be utilized to define the full- 10 depth length of any groove made by the grooving head assembly 24.

The base plate supports a lower slide or grooving head portion 111 which includes parallel slide bars 111a which extend in a direction perpendicular to that of the tracks 97, 98. An upper slide or grooving head portion 112 is slidably supported on the slide bars 111a and includes a number of rigidly joined elements which collectively serve as support means for various movable components described below. A double acting air cylinder 113, such as of the dual type, is connected between the lower portion 111 and the upper portion 112 through an adjustable connection 113a. In response to its movement, the cutter support 109 is either retracted from the belt B to facilitate removal and installation of such belt, or is advanced to position the cutters thereof adjacent to the belt B at the proper distance therefrom preparatory to grooving. The actuator 113 thus provides movement of the cutter support 109 toward and away from the belt B, the extent of which movement toward the belt may be limited by the position of an adjustable stop Hill. The stop 11111 thus defines the distance that the cutter support 109 can be moved toward the belt B, and thereby further defines the depth of the groove produced in the belt B.

The cutter support 109 includes or is carried on a rotatable shaft 114 which is rotatably supported on the upper slide structure 112 shown in FIGURE 10. As best seen in FIGURE 11, the shaft 114 is threaded at two central portions thereof indicated at 114a, 114a which carry coacting nuts 115, 115 which jointly support the cutter assembly therebetween in a vertically adjustable position. The shaft 114 is rotatably supported at its ends by the upper slide or support means 112 by appropriate bearings (FIGURE 10), there being optionally provided a friction brake 116 at the upper end which continually applies a slight drag to the shaft 114. A spur gear 117 with an optional radially apertured ring 118 secured thereto, is carried on the lower end of the shaft 114 and is corotatable therewith, such as by keying. The shaft 114 is effectively rotated in increments of 45 by rotational forces applied to the cutter gear 117.

The structure for rotating and locking the cutter gear 117 is seen in FIGURE 10' to the left of the shaft 114, and is better seen in FIGURES 10a and 12 and viewed from above. Secured to the upper slide or supporting means 112 is a pivot plate 119 which is pivotal about a pivot-defining means 120 in response to reciprocation of a double-acting air cylinder 121 between limits of engagement defined by a stop plate 122 having stop surfaces 122a and 12211 engageable with the sides of the pivot plate 119. These components have been illustrated in FIG- URE 12 for clarity in a neutral position, but it will be appreciated that the air cylinder 121 is usually fully extended or retracted, to the extent permitted by the stop surfaces 122a and 12212. The air cylinder 121 is used for reversing the direction in which the cutter assembly is angularly indexed as explained below.

A further double-acting air cylinder 123 is pivotally secured at one end to the pivot plate 119, and at its other end, is secured by an adjustable connection to a ratchet mechanism generally indicated at 124. The ratchet mechanism 124 includes a drive gear 125 which is continually meshed with a reversing gear 126, it being understood that the drive gear 125 or the reversing gear 126 will be in mesh with the cutter gear 117 alternatively in response to the position of the pivot plate 119 as determined by the air cylinder 121. The drive gear 125 has the same number of teeth as the cutter gear 117 so that when the drive gear is driven a predetermined angle about its axis, the cutter gear 117 and hence the shaft 114 will be driven a like angular amount. When the air cylinder 121 is fully extended, only the drive gear 125 will be in mesh with the cutter gear 117, and when the air cylinder 121 is fully retracted, only the reversing gear 126 will be in mesh with the cutter gear 117.

The ratchet mechanism 124 is best understood by a joint reference to FIGURES 10, a and 12. The drive mechanism 124 includes a support shaft 127 rigidly secured to the pivot plate 119 as by a press fit, and the drive gear 125 is rotatably carried on the shaft 127. Also rotatably supported by the shaft 127 is a sleeve 128 having a pawl wheel 128a integral therewith and bolted to the drive gear 125 for corotation. The sleeve 128 is retained against axial removal by a washer 127a held axially in place by a screw 127b, which when they are assembled, functionally comprise a rigid upper end of the shaft 127. The sleeve 128 provides rockable support for a lever arm 129 which has a ratchet drive connection with the sleeve 128 shown in FIGURE 10a. A pair of friction washers 130, 130 and a resiliently loaded cap 131 carried by the sleeve 128 act to provide a constant axial frictional loading between the lever arm 129 and the sleeve 128. Remotely from the axis of the shaft 127, the lever arm 129 is pivotally connected to the air cylinder 123.

The ratchet mechanism 124 further includes a pawl 131 which is pivotally supported on the pivot plate 119, and which is of adjustable effective length for engaging successive teeth 128k of the pawl wheel 128a. The effective length of the pawl 131 determines the precise angular locations in which the cutter shaft 114 may be positioned. The ratchet mechanism 124 further includes a ratchet wheel portion 128c on the sleeve 128, the same being defined .by a series of recesses which define oppositely directed teeth 128d. To coact therewith, the lever arm 129 includes a resiliently biased pin 129a which has a driving face and a cam face coactive with the teeth 128d to enable relative angular movement between the lever arm 129 and the sleeve 128 in one direction, and to preclude such angular relative movement in the opposite direction.

As viewed in FIGURE 12, when the actuator 123 is movably extended, lever arm 129 is driven in a clockwise direction about the sleeve 128, and by virture of the abutting relationship between the pawl 131 and the pawl wheel 128a, the sleeve 128 and the drive gear 125 are held against movement. This angular movement continues until the pin 129a of the lever arm 129 is received between the next pair of teeth 128d, as illustrated. Any of further extension of the air cylinder 123 merely causes the pin 129a to tend to slip again with respect to the ratchet wheel 128a. Thus, the cutter gear 117 and the cutter support shaft 114 are held against angular movement if either of the gears 125 or 126 is engaged therewith. When the actuator 123 is then retracted, it acts through the lever arm 129 and its pin 129a to rotate the sleeve 128 through the engaged tooth 128d, and thereby also rotate the pawl wheel 128a and drive gear 125 in a counterclockwise direction. When the gear 125 is engaged with the cutter gear 117, it is apparent that such driving movement will also rotate the cutter shaft 114, but in a clockwise direction. Although the pawl teeth 1281) are spaced uniformly 45 apart, and although the ratchet teeth 128d are likewise spaced a uniform 45 apart, there is a slight angular offset between these two sets of teeth, such offset being so arranged that when the sleeve is driven through the teeth 128d, the pawl 131 will drop off the adjacent pawl tooth 128b before the cutter movement terminates. Further, the ratchet teeth 128d are so located that when the actuator 123 is moved to the end of its cutter-rotating stroke, the cutter shaft 114 will have been rotated to and through the ultimately desired angular position thereof so that the cutters thereon will have been advanced by a few degrees beyond the point at which the pawl teeth will lock the same. The pawl teeth are so arranged that when the cutter is translated by action of the motor 100, a reactive force from the belt B will act through the cutter to rotate the cutter shaft 114 reversely, and hence also the cutter gear 117 and drive gear 125 to a point where the pawl 131 engages the abutment at the previous pawl tooth 128b.

We have found that this overdriven initial travel provides a lost motion connection or backlash in the system which enables a rapid start-up of translation on the track 97, 98 without breaking the cutter.

When the cutter shaft is to be advanced again, the previous cycle is repeated so as to index the cutter shaft 114 to the next position.

If desired, an interlock may be provided to sense and to indicate that the cutter shaft 114 has been rotated to a proper position. Thus, if desired, and to this end, there may be provided a plunger or rod 132 having a cam-like inner end coactive with the radially apertured ring 118, and operative to close a suitable electric switch 133 forming a part of the control system. It is to be understood that either the plunger 132 or the edges of the radially directed apertures 118a may be provided with the camlike construction.

The cutter support or assembly 109 includes an annular body 134 slidably disposed on and keyed to the shaft 114. The annular body 134 includes a number of axially directed slots 134a, and a group of internal threads. These threads engage with corresponding threads in a sleeve nut 135, the nut 135 having a flange 135a. At the opposite end of the annular body 134, there is a clamping ring 136 and a sleeve 137. The sleeve nut 135 and the sleeve 137 are disposed between washers and are held on the shaft 114 by the nuts 115, as earlier explained. Between the flange 135a and the clamping ring 136, there is disposed a number of additional clamping rings and spacers which extend about the annular body 134. Tightening of the sleeve nut 135 effects axial clamping of all such additional clamping rings and spacers.

The cutter assembly 109 includes a number of cutters, the illustrated embodiment having eight separate cutters. Each cutter or cutter blade or knife blade in this embodiment is identical to the others, the cutter blade 138 therefore being typical. The cutter blade 138 initially comprises a length of tool steel approximately three-sixteenths to one-fourth inch in width, and approximately .020 inch in initial thickness. The cutter blade material is formed in a U-shape such as shown in FIG. 1. The legs of the U-shape are clamped between suitably spaced clamping rings and also extend radially inwardly into one of the slots 134a in the annular body 134.

FIG. 11a illustrates the preferred mode of sharpening. The cross-section illustrated in FIG. 11a is that which is provided for substantially the entire portion of a U-shape which extends outwardly of the various clamping rings. It will be noted that approximately one-third of the width of the blade 138 is ground away from each edge, the blade thickness being greatly exaggerated in FIG. 11a for clarity of illustration. Further, the material is so removed that opposite edges of the blade 138 comprise knife or cutting edges, such edges being substantially coplanar with the inner surface of the U-shape. Thus, when one edge 138a comprises the leading edge passing through rubber, there is provided a trailing recess 13% on the outside of the cutter. The recess 13812 combined with the internally disposed cutting edge 138a comprises a structure which 'may be utilized at room temperature for cutting rubber at room temperature, the resulting out being one that is produced without galling and one that is exceptionally smooth to the touch. We have found that a cutter structure 138 is employed of the type described and shown herein, the chip of rubber removed remains intact as a single piece which, as it passes through the cutter 138 as shown in the righthand portion of FIG. 11, usually stays in the groove, but is readily removed therefrom as by pushing.

In FIG. 2 there is shown a fragmentary portion of a pattern which may be provided in a massive rubber belt B. (The reader is referred to the Beachler et a1. U.S. Patent No. 3,025,910 for further information on belts of this type.) It will be noted that the pattern in FIG. 2 

1. A DEVICE FOR MACHINING A MASSIVE BELT COMPRISING IN COMBINATION: (A) A PLURALITY OF MEANS FOR SUPPORTING THE BELT FOR ROTATION ABOUT A PLURALITY OF PARALLEL AXES; (B) A DRIVE MECHANISM DRIVABLY CONNECTED TO SAID BELTSUPPORT MEANS, SAID DRIVE MECHANISM INCLUDING SELECTIVELY OPERATIVE MEANS FOR ROTATING THE BELT CONTINUALLY AND ALSO FOR ROTATING THE BELT INCREMENTALLY; AND (C) A MACHINING HEAD SUPPORTED ADJACENT TO THE BELT, AND ADAPTED TO REMOVE PART OF THE MATERIAL OF THE BELT BETWEEN INCREMENTS OF ROTATION THEREOF. 